esp.c

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		sti();

		for (i = 0; i < space_avail - 1; i += 2) {
			outw(*((unsigned short *)(pio_buf->data + i)),
			     info->port + UART_ESI_TX);
		}

		if (space_avail & 0x0001)
			serial_out(info, UART_ESI_TX,
				   pio_buf->data[space_avail - 1]);

		cli();

		if (info->xmit_cnt) {
			serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
			serial_out(info, UART_ESI_CMD1, ESI_GET_TX_AVAIL);
			space_avail = serial_in(info, UART_ESI_STAT1) << 8;
			space_avail |= serial_in(info, UART_ESI_STAT2);

			if (space_avail > info->xmit_cnt)
				space_avail = info->xmit_cnt;
		}
	}

	if (info->xmit_cnt < WAKEUP_CHARS) {
		rs_sched_event(info, ESP_EVENT_WRITE_WAKEUP);

#ifdef SERIAL_DEBUG_INTR
		printk("THRE...");
#endif

		if (info->xmit_cnt <= 0) {
			info->IER &= ~UART_IER_THRI;
			serial_out(info, UART_ESI_CMD1,
				   ESI_SET_SRV_MASK);
			serial_out(info, UART_ESI_CMD2, info->IER);
		}
	}

	release_pio_buffer(pio_buf);
}

static _INLINE_ void transmit_chars_dma(struct esp_struct *info, int num_bytes)
{
	unsigned long flags;
	
	dma_bytes = num_bytes;

	if (info->xmit_tail + dma_bytes <= ESP_XMIT_SIZE) {
		memcpy(dma_buffer, &(info->xmit_buf[info->xmit_tail]),
		       dma_bytes);
	} else {
		int i = ESP_XMIT_SIZE - info->xmit_tail;
		memcpy(dma_buffer, &(info->xmit_buf[info->xmit_tail]),
			i);
		memcpy(&(dma_buffer[i]), info->xmit_buf, dma_bytes - i);
	}

	info->xmit_cnt -= dma_bytes;
	info->xmit_tail = (info->xmit_tail + dma_bytes) & (ESP_XMIT_SIZE - 1);

	if (info->xmit_cnt < WAKEUP_CHARS) {
		rs_sched_event(info, ESP_EVENT_WRITE_WAKEUP);

#ifdef SERIAL_DEBUG_INTR
		printk("THRE...");
#endif

		if (info->xmit_cnt <= 0) {
			info->IER &= ~UART_IER_THRI;
			serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
			serial_out(info, UART_ESI_CMD2, info->IER);
		}
	}

	info->stat_flags |= ESP_STAT_DMA_TX;
	
	flags=claim_dma_lock();
        disable_dma(dma);
        clear_dma_ff(dma);
        set_dma_mode(dma, DMA_MODE_WRITE);
        set_dma_addr(dma, virt_to_bus(dma_buffer));
        set_dma_count(dma, dma_bytes);
        enable_dma(dma);
        release_dma_lock(flags);
        
        serial_out(info, UART_ESI_CMD1, ESI_START_DMA_TX);
}

static _INLINE_ void transmit_chars_dma_done(struct esp_struct *info)
{
	int num_bytes;
	unsigned long flags;
	

	flags=claim_dma_lock();
	disable_dma(dma);
	clear_dma_ff(dma);

	num_bytes = dma_bytes - get_dma_residue(dma);
	info->icount.tx += dma_bytes;
	release_dma_lock(flags);

	if (dma_bytes != num_bytes) {
		dma_bytes -= num_bytes;
		memmove(dma_buffer, dma_buffer + num_bytes, dma_bytes);
		
		flags=claim_dma_lock();
        	disable_dma(dma);
        	clear_dma_ff(dma);
        	set_dma_mode(dma, DMA_MODE_WRITE);
        	set_dma_addr(dma, virt_to_bus(dma_buffer));
        	set_dma_count(dma, dma_bytes);
        	enable_dma(dma);
        	release_dma_lock(flags);
        	
        	serial_out(info, UART_ESI_CMD1, ESI_START_DMA_TX);
	} else {
		dma_bytes = 0;
		info->stat_flags &= ~ESP_STAT_DMA_TX;
	}
}

static _INLINE_ void check_modem_status(struct esp_struct *info)
{
	int	status;
	
	serial_out(info, UART_ESI_CMD1, ESI_GET_UART_STAT);
	status = serial_in(info, UART_ESI_STAT2);

	if (status & UART_MSR_ANY_DELTA) {
		/* update input line counters */
		if (status & UART_MSR_TERI)
			info->icount.rng++;
		if (status & UART_MSR_DDSR)
			info->icount.dsr++;
		if (status & UART_MSR_DDCD)
			info->icount.dcd++;
		if (status & UART_MSR_DCTS)
			info->icount.cts++;
		wake_up_interruptible(&info->delta_msr_wait);
	}

	if ((info->flags & ASYNC_CHECK_CD) && (status & UART_MSR_DDCD)) {
#if (defined(SERIAL_DEBUG_OPEN) || defined(SERIAL_DEBUG_INTR))
		printk("ttys%d CD now %s...", info->line,
		       (status & UART_MSR_DCD) ? "on" : "off");
#endif		
		if (status & UART_MSR_DCD)
			wake_up_interruptible(&info->open_wait);
		else if (!((info->flags & ASYNC_CALLOUT_ACTIVE) &&
			   (info->flags & ASYNC_CALLOUT_NOHUP))) {
#ifdef SERIAL_DEBUG_OPEN
			printk("scheduling hangup...");
#endif
			MOD_INC_USE_COUNT;
			if (schedule_task(&info->tqueue_hangup) == 0)
				MOD_DEC_USE_COUNT;
		}
	}
}

/*
 * This is the serial driver's interrupt routine
 */
static void rs_interrupt_single(int irq, void *dev_id, struct pt_regs * regs)
{
	struct esp_struct * info;
	unsigned err_status;
	unsigned int scratch;

#ifdef SERIAL_DEBUG_INTR
	printk("rs_interrupt_single(%d)...", irq);
#endif
	info = (struct esp_struct *)dev_id;
	err_status = 0;
	scratch = serial_in(info, UART_ESI_SID);

	cli();
	
	if (!info->tty) {
		sti();
		return;
	}

	if (scratch & 0x04) { /* error */
		serial_out(info, UART_ESI_CMD1, ESI_GET_ERR_STAT);
		err_status = serial_in(info, UART_ESI_STAT1);
		serial_in(info, UART_ESI_STAT2);

		if (err_status & 0x01)
			info->stat_flags |= ESP_STAT_RX_TIMEOUT;

		if (err_status & 0x20) /* UART status */
			check_modem_status(info);

		if (err_status & 0x80) /* Start break */
			wake_up_interruptible(&info->break_wait);
	}
		
	if ((scratch & 0x88) || /* DMA completed or timed out */
	    (err_status & 0x1c) /* receive error */) {
		if (info->stat_flags & ESP_STAT_DMA_RX)
			receive_chars_dma_done(info, err_status);
		else if (info->stat_flags & ESP_STAT_DMA_TX)
			transmit_chars_dma_done(info);
	}

	if (!(info->stat_flags & (ESP_STAT_DMA_RX | ESP_STAT_DMA_TX)) &&
	    ((scratch & 0x01) || (info->stat_flags & ESP_STAT_RX_TIMEOUT)) &&
	    (info->IER & UART_IER_RDI)) {
		int num_bytes;

		serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
		serial_out(info, UART_ESI_CMD1, ESI_GET_RX_AVAIL);
		num_bytes = serial_in(info, UART_ESI_STAT1) << 8;
		num_bytes |= serial_in(info, UART_ESI_STAT2);

		if (num_bytes > (TTY_FLIPBUF_SIZE - info->tty->flip.count))
		  num_bytes = TTY_FLIPBUF_SIZE - info->tty->flip.count;

		if (num_bytes) {
			if (dma_bytes ||
			    (info->stat_flags & ESP_STAT_USE_PIO) ||
			    (num_bytes <= info->config.pio_threshold))
				receive_chars_pio(info, num_bytes);
			else
				receive_chars_dma(info, num_bytes);
		}
	}
	
	if (!(info->stat_flags & (ESP_STAT_DMA_RX | ESP_STAT_DMA_TX)) &&
	    (scratch & 0x02) && (info->IER & UART_IER_THRI)) {
		if ((info->xmit_cnt <= 0) || info->tty->stopped) {
			info->IER &= ~UART_IER_THRI;
			serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
			serial_out(info, UART_ESI_CMD2, info->IER);
		} else {
			int num_bytes;

			serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
			serial_out(info, UART_ESI_CMD1, ESI_GET_TX_AVAIL);
			num_bytes = serial_in(info, UART_ESI_STAT1) << 8;
			num_bytes |= serial_in(info, UART_ESI_STAT2);

			if (num_bytes > info->xmit_cnt)
				num_bytes = info->xmit_cnt;

			if (num_bytes) {
				if (dma_bytes ||
				    (info->stat_flags & ESP_STAT_USE_PIO) ||
				    (num_bytes <= info->config.pio_threshold))
					transmit_chars_pio(info, num_bytes);
				else
					transmit_chars_dma(info, num_bytes);
			}
		}
	}

	info->last_active = jiffies;

#ifdef SERIAL_DEBUG_INTR
	printk("end.\n");
#endif
	sti();
}

/*
 * -------------------------------------------------------------------
 * Here ends the serial interrupt routines.
 * -------------------------------------------------------------------
 */

/*
 * This routine is used to handle the "bottom half" processing for the
 * serial driver, known also the "software interrupt" processing.
 * This processing is done at the kernel interrupt level, after the
 * rs_interrupt() has returned, BUT WITH INTERRUPTS TURNED ON.  This
 * is where time-consuming activities which can not be done in the
 * interrupt driver proper are done; the interrupt driver schedules
 * them using rs_sched_event(), and they get done here.
 */
static void do_serial_bh(void)
{
	run_task_queue(&tq_esp);
}

static void do_softint(void *private_)
{
	struct esp_struct	*info = (struct esp_struct *) private_;
	struct tty_struct	*tty;
	
	tty = info->tty;
	if (!tty)
		return;

	if (test_and_clear_bit(ESP_EVENT_WRITE_WAKEUP, &info->event)) {
		if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
		    tty->ldisc.write_wakeup)
			(tty->ldisc.write_wakeup)(tty);
		wake_up_interruptible(&tty->write_wait);
	}
}

/*
 * This routine is called from the scheduler tqueue when the interrupt
 * routine has signalled that a hangup has occurred.  The path of
 * hangup processing is:
 *
 * 	serial interrupt routine -> (scheduler tqueue) ->
 * 	do_serial_hangup() -> tty->hangup() -> esp_hangup()
 * 
 */
static void do_serial_hangup(void *private_)
{
	struct esp_struct	*info = (struct esp_struct *) private_;
	struct tty_struct	*tty;
	
	tty = info->tty;
	if (tty)
		tty_hangup(tty);
	MOD_DEC_USE_COUNT;
}

/*
 * ---------------------------------------------------------------
 * Low level utility subroutines for the serial driver:  routines to
 * figure out the appropriate timeout for an interrupt chain, routines
 * to initialize and startup a serial port, and routines to shutdown a
 * serial port.  Useful stuff like that.
 * ---------------------------------------------------------------
 */

static _INLINE_ void esp_basic_init(struct esp_struct * info)
{
	/* put ESPC in enhanced mode */
	serial_out(info, UART_ESI_CMD1, ESI_SET_MODE);
	
	if (info->stat_flags & ESP_STAT_NEVER_DMA)
		serial_out(info, UART_ESI_CMD2, 0x01);
	else
		serial_out(info, UART_ESI_CMD2, 0x31);

	/* disable interrupts for now */
	serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
	serial_out(info, UART_ESI_CMD2, 0x00);

	/* set interrupt and DMA channel */
	serial_out(info, UART_ESI_CMD1, ESI_SET_IRQ);

	if (info->stat_flags & ESP_STAT_NEVER_DMA)
		serial_out(info, UART_ESI_CMD2, 0x01);
	else
		serial_out(info, UART_ESI_CMD2, (dma << 4) | 0x01);

	serial_out(info, UART_ESI_CMD1, ESI_SET_ENH_IRQ);

	if (info->line % 8)	/* secondary port */
		serial_out(info, UART_ESI_CMD2, 0x0d);	/* shared */
	else if (info->irq == 9)
		serial_out(info, UART_ESI_CMD2, 0x02);
	else
		serial_out(info, UART_ESI_CMD2, info->irq);

	/* set error status mask (check this) */
	serial_out(info, UART_ESI_CMD1, ESI_SET_ERR_MASK);

	if (info->stat_flags & ESP_STAT_NEVER_DMA)
		serial_out(info, UART_ESI_CMD2, 0xa1);
	else
		serial_out(info, UART_ESI_CMD2, 0xbd);

	serial_out(info, UART_ESI_CMD2, 0x00);

	/* set DMA timeout */
	serial_out(info, UART_ESI_CMD1, ESI_SET_DMA_TMOUT);
	serial_out(info, UART_ESI_CMD2, 0xff);

	/* set FIFO trigger levels */
	serial_out(info, UART_ESI_CMD1, ESI_SET_TRIGGER);
	serial_out(info, UART_ESI_CMD2, info->config.rx_trigger >> 8);
	serial_out(info, UART_ESI_CMD2, info->config.rx_trigger);
	serial_out(info, UART_ESI_CMD2, info->config.tx_trigger >> 8);
	serial_out(info, UART_ESI_CMD2, info->config.tx_trigger);

	/* Set clock scaling and wait states */
	serial_out(info, UART_ESI_CMD1, ESI_SET_PRESCALAR);
	serial_out(info, UART_ESI_CMD2, 0x04 | ESPC_SCALE);

	/* set reinterrupt pacing */
	serial_out(info, UART_ESI_CMD1, ESI_SET_REINTR);
	serial_out(info, UART_ESI_CMD2, 0xff);
}

static int startup(struct esp_struct * info)
{
	unsigned long flags;
	int	retval=0;
        unsigned int num_chars;

	save_flags(flags); cli();

	if (info->flags & ASYNC_INITIALIZED)
		goto out;

	if (!info->xmit_buf) {
		info->xmit_buf = (unsigned char *)get_free_page(GFP_KERNEL);
		retval = -ENOMEM;
		if (!info->xmit_buf)
			goto out;
	}

#ifdef SERIAL_DEBUG_OPEN
	printk("starting up ttys%d (irq %d)...", info->line, info->irq);
#endif

	/* Flush the RX buffer.  Using the ESI flush command may cause */
	/* wild interrupts, so read all the data instead. */

	serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
	serial_out(info, UART_ESI_CMD1, ESI_GET_RX_AVAIL);
	num_chars = serial_in(info, UART_ESI_STAT1) << 8;
	num_chars |= serial_in(info, UART_ESI_STAT2);

	while (num_chars > 1) {
		inw(info->port + UART_ESI_RX);
		num_chars -= 2;
	}

	if (num_chars)
		serial_in(info, UART_ESI_RX);

	/* set receive character timeout */
	serial_out(info, UART_ESI_CMD1, ESI_SET_RX_TIMEOUT);
	serial_out(info, UART_ESI_CMD2, info->config.rx_timeout);

	/* clear all flags except the "never DMA" flag */
	info->stat_flags &= ESP_STAT_NEVER_DMA;

	if (info->stat_flags & ESP_STAT_NEVER_DMA)
		info->stat_flags |= ESP_STAT_USE_PIO;

	/*
	 * Allocate the IRQ
	 */

	retval = request_irq(info->irq, rs_interrupt_single, SA_SHIRQ,
			     "esp serial", info);

	if (retval) {
		if (capable(CAP_SYS_ADMIN)) {
			if (info->tty)
				set_bit(TTY_IO_ERROR,
					&info->tty->flags);
			retval = 0;
		}
		goto out;
	}

	if (!(info->stat_flags & ESP_STAT_USE_PIO) && !dma_buffer) {
		dma_buffer = (char *)__get_dma_pages(
			GFP_KERNEL, get_order(DMA_BUFFER_SZ));

		/* use PIO mode if DMA buf/chan cannot be allocated */
		if (!dma_buffer)
			info->stat_flags |= ESP_STAT_USE_PIO;
		else if (request_dma(dma, "esp serial")) {
			free_pages((unsigned long)dma_buffer,
				   get_order(DMA_BUFFER_SZ));
			dma_buffer = 0;
			info->stat_flags |= ESP_STAT_USE_PIO;
		}
			
	}

	info->MCR = UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2;
	serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
	serial_out(info, UART_ESI_CMD2, UART_MCR);
	serial_out(info, UART_ESI_CMD2, info->MCR);
	
	/*
	 * Finally, enable interrupts
	 */
	/* info->IER = UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI; */
	info->IER = UART_IER_RLSI | UART_IER_RDI | UART_IER_DMA_TMOUT |
			UART_IER_DMA_TC;
	serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
	serial_out(info, UART_ESI_CMD2, info->IER);
	
	if (info->tty)
		clear_bit(TTY_IO_ERROR, &info->tty->flags);